Nearly 50,000 are still waiting on the state to process their applications, despite Gov. Martin O’Malley having offered “all the resources necessary” to get through the backlog before October. Maryland State Police announced that anyone still waiting on Tuesday will have the new application requirements waived.

There’s an obvious logic to that decision. But the whole thing points to an inherent problem with this type of gun control measure. If current gun owners are grandfathered in and new regulations cause an initial spike in gun purchases, what’s the horizon on the new gun law? Even assuming it’s ingeniously crafted, how long will we have to wait before its effects can be seen?